The present invention relates to an apparatus for recovering, refining, and storing hydrogen gas. The apparatus enables used hydrogen gas having a low purity to be reused for a hydrogen furnace or as a process gas by refining the used hydrogen gas and storing the refined hydrogen gas.
As hydrogen gas for a hydrogen furnace or as a process gas, or the like, there is used hydrogen gas having a high purity of 99.9% or more so as to avoid oxidation and carbonization of is products. However, the purity drops to 70-99.0% because impure gas, or the like, is mixed therein. Hydrogen gas of decreased purity has conventionally been regarded as an unreusable gas and disposed of by combustion.
When hydrogen gas is carried by a loader out of a hydrogen manufacturing operation to a tank, or when hydrogen gas is produced with an on-site hydrogen producing apparatus, disposal of hydrogen by combustion after every use has had a great loss in view of energy saving and cost.
There has been proposed an apparatus for refining hydrogen gas having a decreased purity with a hydrogen occlusion alloy as a technique to highly purify and reuse a hydrogen gas having a decreased purity by refining. In the apparatus, hydrogen gas having a decreased purity is introduced into a refinement container, only hydrogen gas is absorbed by a hydrogen occlusion alloy installed in the refinement container, the remaining impurity is discharged from the system, and then the hydrogen gas is released from the hydrogen occlusion alloy to be stored in a tank.
However, in the aforementioned apparatus, repeated occlusion of hydrogen gas pulverizes the hydrogen occlusion alloy, and it sometimes happens that the pulverized alloy is mixed in the hydrogen gas.
Release of hydrogen gas from the hydrogen occlusion alloy is an endothermic reaction, while occlusion of hydrogen gas by the hydrogen occlusion alloy is an exothermic reaction. Therefore, the hydrogen occlusion alloy has to be subjected alternatively to heating and cooling so as to occlude and release hydrogen gas. Thus, the apparatus requires a complex treatment.
Further, in the aforementioned apparatus, it has been difficult to continuously supply a certain amount of a refined gas because one refinement container is not sufficient for simultaneously conducting occlusion and release. Accordingly, two or more refinement containers have generally been used and operated by alternating the containers so that one is in an occlusion process when the other is in release process. Since a fluctuation of an amount of supply of a refined gas has been controlled to be small, the operation was complex, and the structure of the apparatus has become more intricate.
The present invention was made in consideration of the aforementioned conditions. The object of the present invention is to provide a recovery, refinement, and storage apparatus for hydrogen gas which is free from mixing with a pulverized alloy, which apparatus is easily operated, the structure of which is simple, and which can continuously supply a certain amount of refined gas.